Frequency domain noise analysis of optoelectronic oscillators considering the nonlinearity of the RF amplifier

چکیده مقاله

A new, physically consistent approach for modeling the nonlinearity of a radio frequency (RF) amplifier within an optoelectronic oscillator (OEO) structure that uses the measured amplitude and phase responses of the RF amplifier is presented. This behavioral model, along with the measured frequency response of the RF filter, is used in frequency domain to predict the signal and noise spectrum of the OEO based on the well-known conversion matrix approach. A simple technique for computing the steady state of the OEO with high precision is introduced that prevents the ill-conditioning problem in computing the phase and amplitude noise power spectral densities at the near-carrier offset frequencies. The validity of this approach is verified by the previously published data in the literature. By considering a hypothetical phase response for the RF amplifier, it is shown that the presented nonlinear modeling and the analysis algorithm are capable of taking the important phenomenon of amplitudeto- phase conversion, which is responsible for converting the amplitude fluctuations into phase noise, into account.